Color photographic materials for prints, slides, camera shots, instant photographs and the like are generally exposed to various environmental conditions in the manufacture thereof as well as during or after the photographic processing thereof. Therefore, it is difficult to keep the material, which mainly comprises a gelatin component, in the form of an optically uniform film. Often, such exposure results in the occurrence of a fine roughness of the surface of the film or in the reduction of the light transmittance of the film.
These phenomena cause an extreme deterioration in the beauty of the images formed in the photographs with the result being that the planned characteristics of the photographic materials cannot sufficiently be attained.
In such color photographic materials, at least one hydrophilic colloid layer therein contains a large oil component and the adjacent hydrophilic colloid layers do not contain any oil component or contain only a relatively small amount of an oil component. Each layer, however, is not uniformly elastic relative to the variation of the environmental conditions, such as temperature, humidity as well as pH and salt concentration in the processing solutions. Also, the balance of the layers is apt to be lost. Therefore, the aforesaid phenomena will occur very often in color photographic materials.
Under the circumstances, with multilayer color photographic materials having a gelatin film containing a large oil component, it was necessary to severely control the ratio of the oil component to gelatin in each layer so that the ratio does not largely vary in each layer. This was necessary in order to keep a uniform film surface throughout the manufacturing steps of the materials, the taking of photographs therewith, the photographic processing thereof and the preservation of the photographs after the processing, thereby to obtain the photographs of high quality.
However, the incorporation of a large amount of an oil component especially in the outermost surface layer of photographic materials caused the bleeding of the oil component out of the surface layer in the manufacture of the material. Therefore, in practice, the content of the oil component in the outermost surface layer must be low or the outermost surface layer must be free from any oil component.
In order to solve this problem, various means have heretofore been proposed and actually tried. For example, reducing the amount of oil component in the material, controlling the salt concentration in the photographic processing step, controlling the temperature in the processing bath, controlling the drying temperature after the processing step or covering the material with a special protective film so that the material after processing is not directly exposed to the environmental atmosphere.
Further, a polyvinyl alcohol or the graft polymer thereof, as described in Japanese Patent Publication No. 47371/80, has been added to the hydrophilic colloid layer so as to modify the physical and mechanical property of the film.
In the above trails, the former means is insufficient in view of the requirements that the quality of the photographs is to be kept high and that other troubles must not result therefrom. Further, this means is complicated and is not economical.
The latter means where a polyvinyl alcohol or the graft polymer thereof is used, is also defective in that the balance of the layers is not improved but on the contrary the photographic density is reduced and the film surface is not uniform but rough.
Accordingly, the first object of the present invention is to provide photographic light-sensitive materials which are free from the aforesaid problems and which may form excellent images.
The second object of the present invention is to improve the interlayer adhesion of the layers in the photographic materials and to provide materials where the layers are not cleaved in the manufacture thereof or during or after the photographic processing thereof.
The third object of the present invention is to provide photographic materials capable of forming photographic images with excellent gloss in various photographic processing environments such as high temperature and high speed processing and following high temperature drying.
The use of a fluorescent whitening agent for the purpose of improving the whiteness of photographic light-sensitive materials after processing is well known in this technical field. In recent years, photographic light-sensitive materials that are suitable for a simple and rapid processing have been necessary. Therefore, various techniques have been developed therefor. For example, the incorporation of black-and-white developing agents such as hydroquinones, metals and phenidones or color developing agents such as p-phenylenediamine derivatives in the photographic materials, high temperature processing and high speed processing of the materials are included. In high speed processing where the processing time is short, however, the residual coloration of sensitizer colors or dyes is apt to occur. Under these conditions, accordingly, the increment of the whiteness of the materials because of the addition of a fluorescent whitening agent is more and more important in the provision of photographic papers.
It is a matter of course that the fluorescent whitening means may generally be utilized for the purpose of improving the apparent whiteness of the materials, irrespective of the occurrence of the residual coloration therein.
Various methods are known for fluorescent whitening of photographic light-sensitive materials. For example, fluorescent whitening agents have been added to the paper support or to the polyethylene laminate layer thereof or water-soluble fluorescent whitening agents or oil-soluble fluorescent whitening agents have been directly added to a silver halide emulsion layer or to other photographic layers coated on a support. These methods are described in Japanese Patent Application (OPI) No. 117/78 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"), U.S. Pat. Nos. 3,449,257, 3,501,298 and 3,558,316. There are also methods where a fluorescent whitening agent is dispersed in a polymer or is dissolved and dispersed in a so-called photographic dispersing agent and then is added to the photographic materials. These methods are described in Japanese Patent Publications Nos. 37376/70, 11111/70 and 47043/76, U.S. Pat. Nos. 3,416,923 and 3,418,127. Fluorescent whitening agents such as a water-soluble diaminostilbene derivatives have also been previously incorpoated in a developer solution and the agent is penetrated into the photographic materials when processed with the developer. The conventional methods, however, are defective especially in the case where fluorescent whitening agents are incorporated into the laminate layer of the polyethylene laminate paper which is suitable for rapid processing, because the fluorescent whitening agents are poor in the thermal stability and the agents often decompose in the step of heat extrusion during formation of the laminate layer. Further, the fluorescent agents are poor in heat sublimation resistance, and, therefore, the agents are apt to adhere to the manufacturing apparatus. Moreover, the above methods require the regulation of the amount of the fluorescent whitening agent to be added, if photographic materials which may be applied to various kinds of uses and objects are to be formed. Therefore, it is apparent that considerable time, labor and expense are necessary. Thus, the methods are practically limited and, in fact, can hardly be practiced.
Other methods are known where a fluorescent whitening agent is added to a photographic layer. In particular, there is a method where an oil-soluble fluorescent whitening agent is incorporated in a photographic material since the agent does not flow out and thus is not lost during the development processing of the material. There is also a method where a water-insoluble fluorescent whitening agent is dissolved in an organic solvent and the emulsified dispersion is incorporated in a gelatin layer. This method is described in British Patent 1,072,915.
The aforesaid conventional methods where a water-soluble fluorescent whitening agent is incorporated in the processing solution and is diffused into the photographic material or where the water-insoluble fluorescent whitening agent is added to the photographic material are defective in that the fluorescent whitening agent often precipitates or decomposes. This results in the reduction of the whiteness of the material or rather results in the occurrence of stains in the material when the materials are preserved for a long period of time after the photographic processing thereof. In order to improve the whiteness, the fluorescent strength of the fluorescent whitening agent as well as the fluorescent emission spectrum distribution and optical and thermal stability thereof are important factors.
A number of fluorescent whitening agents with improved fluorescent strength and optical and thermal stability have heretofore been developed. However, there are relatively few compounds which are photographically harmless and are sufficiently effective.
Under these circumstances, both in the method where the water-soluble fluorescent whitening agent is penetrated into the photographic material from the processing solution and in the method where the water-insoluble fluorescent whitening agent is dissolved and dispersed in an oil and is added to the photographic material, it is important to stabilize the fluorescent whitening agent in the layers of the photographic material for a long period of time after the photographic processing of the material.
A number of compounds are added to the highly efficient photographic materials, and a number of compounds are also added to the developer and other processing solutions. It is known that these additive compounds include a compound having a quenching activity.
When the photographic light-sensitive materials are processed and preserved, stabilizing the fluorescent whitening agent-containing polymer film thereof under environmental circumstances is an important factor for retaining the effect of the fluorescent whitening agent for a long period of time.
In order to keep the efficient effect of the fluorescent whitening agent in the materials, a technique is known to add a polyvinyl pyrrolidone or polyvinyl alcohol to the gelatin binder which is generally used in the photographic materials. This technique is described in Japanese Patent Publication No. 7127/59. The addition of such polymers has various problems, however, including the occurrence of development inhibition, a reduction in the film strength of the photographic layers, the formation of rough surfaces after photographic processing, a deterioration of adhesion strength of the photographic layers and the occurrence of haze on the film surface.
Accordingly, the fourth object of the present invention is to develop silver halide photographic materials which are free from the aforesaid problems and which may form prints with excellent background whiteness.
The fifth object of the present invention is to develop the silver halide photographic materials which may form prints with excellent background whiteness by rapid development processing.
The sixth object of the present invention is to develop silver halide photographic materials which may form prints with less reduction of the background whiteness during the preservation of the materials.
The seventh object of the present invention is to develop silver halide photographic materials capable of forming prints where the fluorescent whitening agent contained therein does not precipitate during the preservation of the materials.
The eighth object of the present invention is to provide a method for processing photographic materials for the formation of prints with excellent background whiteness.
The ninth object of the present invention is to provide prints with excellent background whiteness.